Bio-electrical Impedance

**BadBarbie** · 08-02-2008, 09:06 PM

I know it already isn't 100% accurate but..

Tonight after my workout I was in the steam room for about a half an hour so I was basically completely dehydrated. I then measured my bf% using B.I. and it said 18.0%. I heard when you are dehydrated though it will show a lot higher than you really are because water conducts electricity easy like muscle does so when I don't have any water in me, the electricity moves slower, like through fat. Is this true? If it is, how much lower would I really be?

Also, I'm on a cycle now, so I'm not sure if that makes a difference.

**hotpink** · 08-02-2008, 09:07 PM

I don't know the answer, but I'm pretty sure you are way less than 18%

**daem** · 08-02-2008, 09:10 PM

Originally Posted by BadBarbie

I know it already isn't 100% accurate but..

Tonight after my workout I was in the steam room for about a half an hour so I was basically completely dehydrated. I then measured my bf% using B.I. and it said 18.0%. I heard when you are dehydrated though it will show a lot higher than you really are because water conducts electricity easy like muscle does so when I don't have any water in me, the electricity moves slower, like through fat. Is this true? If it is, how much lower would I really be?

Also, I'm on a cycle now, so I'm not sure if that makes a difference.

[ Edited to not perpetuate something others confirm as false ]

**BadBarbie** · 08-02-2008, 09:14 PM

Originally Posted by daem

Why would you intentionally dehydrate yourself to take a bodyfat test?

I've done the test before under several different circumstances, and I can tell you it's FAIRLY accurate +/- 2% or so.

I didn't dehydrate intentionally for the test. I was just walking out the door and asked if they had a machine because I'd been looking for one (new gym).

I wasn't planning on taking the test when I was in the steam room. It was just a last minute shits and giggles thing.

**one8nine** · 08-02-2008, 09:22 PM

Originally Posted by daem

Why would you intentionally dehydrate yourself to take a bodyfat test?

I've done the test before under several different circumstances, and I can tell you it's FAIRLY accurate +/- 2% or so.

during wrestling season in highscool i think i was about 195 7%
they did bio. imped. to see what weight class we could wrestle
i wanted to wrestle 160
i dehydrated down to 172ish, weiged in, and my bf% read ~27%
they said i could wrestle 152, just missed the 145 mark

**daem** · 08-02-2008, 09:30 PM

Originally Posted by one8nine

during wrestling season in highscool i think i was about 195 7%
they did bio. imped. to see what weight class we could wrestle
i wanted to wrestle 160
i dehydrated down to 172ish, weiged in, and my bf% read ~27%
they said i could wrestle 152, just missed the 145 mark

Interesting...I should revise my FAIRLY accurate statement to be FAIRLY accurate for ME because I've done bio and hydrostatic on the same day and been within 2%.

You lost 20 lbs of water from 195 to 172??

**one8nine** · 08-02-2008, 09:45 PM

Originally Posted by daem

Interesting...I should revise my FAIRLY accurate statement to be FAIRLY accurate for ME because I've done bio and hydrostatic on the same day and been within 2%.

You lost 20 lbs of water from 195 to 172??

yeah ive done worse... i was like 190 and my actual competition weight was 160
wrestling is serious bro i knew kids that were 170 wrestling 125

**Phate** · 08-02-2008, 09:53 PM

Originally Posted by BadBarbie

I know it already isn't 100% accurate but..

Tonight after my workout I was in the steam room for about a half an hour so I was basically completely dehydrated. I then measured my bf% using B.I. and it said 18.0%. I heard when you are dehydrated though it will show a lot higher than you really are because water conducts electricity easy like muscle does so when I don't have any water in me, the electricity moves slower, like through fat. Is this true? If it is, how much lower would I really be?

Also, I'm on a cycle now, so I'm not sure if that makes a difference.

B.I. measures basically how easily electric current flows through your body and works on a couple different principles. Lean body mass, because of it's high water content, conducts electricity much better than fat. So you are right, water content will play a major part in the results.

something else to consider is that most scales that are used only measure your lower body, while most hand held units only measure your upper body, this can also alter your results.

**mkrulic** · 08-02-2008, 10:23 PM

they are way inacurate for me. bout 13% to high

**daem** · 08-02-2008, 10:25 PM

Originally Posted by one8nine

yeah ive done worse... i was like 190 and my actual competition weight was 160
wrestling is serious bro i knew kids that were 170 wrestling 125

Holy mother of moses...I was a football player so I'm uneducated when it comes to wrestling protocol.

That's amazing to me that you'd lose that kind of weight to compete.